The diagnosis and treatment of patients with cancerous tumors, pre-malignant conditions, and other disorders has long been an area of intense investigation. Non-invasive methods for examining tissue include palpation, X-ray, MRI, CT, and ultrasound imaging. When the physician suspects that a tissue may contain cancerous cells, a biopsy may be done using either an open procedure or a percutaneous procedure. For an open procedure, the surgeon creates a large incision within the tissue in order to provide direct viewing and access to the tissue mass of interest. The entire mass (excisional biopsy) or a part of the mass (incisional biopsy) may then be removed. For a percutaneous biopsy, a needle-like instrument is used through a very small incision to access the tissue mass of interest and to obtain a tissue sample for later examination and analysis. The advantages of the percutaneous method as compared to the open method are significant. The procedure is normally done relatively quickly with local anesthetics. Recovery time and the cost of the procedure are diminished, and there is typically much less disfigurement of the patient's anatomy. In addition, use of the percutaneous method in combination with imaging devices such as X-ray and ultrasound has resulted in highly reliable diagnoses and treatments.
Generally there are two ways to obtain percutaneously a portion of tissue from within the body, by aspiration or by core sampling. Aspiration of the tissue through a fine needle requires the tissue to be fragmented into pieces small enough to be withdrawn in a fluid medium. The method is less intrusive than other known sampling techniques but one can only examine cells in the liquid (cytology) and not the cells and the structure (pathology). In core biopsy, a core or fragment of tissue is obtained for histological examination, which may be done via a frozen or paraffin section. The type of biopsy used depends mainly on various factors present in the patient, and no single procedure is ideal for all cases. Core sampling biopsy, however, is very useful in a number of conditions and is widely used by physicians.
A number of core sampling biopsy devices have been developed and commercialized for use in combination with imaging devices. One example is a core sampling biopsy device known as the MAMMOTOME biopsy device marketed by Ethicon Endo-Surgery, Inc., Cincinnati, Ohio. The MAMMOTOME biopsy device is vacuum-assisted and some of the steps for retrieving multiple tissue samples have been automated. The operator uses this device to capture "actively" (using the vacuum) the tissue prior to severing it from the body. This allows for sampling tissues of varying hardness. In the MAMMOTOME biopsy device, a cutting cannula is rotated using a motor drive mounted in the instrument while the operator manually moves the cutting cannula back and forth by a knob on the outside of the instrument. Thus, the operator is able, through tactile feedback, to determine whether the blade is effectively cutting tissue or if there is a problem, such as binding or stalling. The operator may then adjust the speed at which the blade is moved through the tissue, stop the blade, or back the blade away from the tissue. The device can also be used to collect multiple samples in numerous positions about its longitudinal axis, without removing the biopsy needle from the body. These features allow for substantial sampling of large lesions and complete removal of small ones. In the MAMMOTOME biopsy device, a vacuum chamber is attached alongside and fluidly connected to an elongated, hollow piercing element. The vacuum supplied through the vacuum chamber pulls tissue into a lateral receiving port of the hollow piercing element. This type of vacuum-assisted biopsy device is disclosed in U.S. Pat. No. 5,649,547 issued to Ritchart, et al, on Jul. 22, 1997.
The MAMMOTOME biopsy device may be used with a handheld, real-time imaging ultrasonic device, or with numerous kinds of X-ray stereotactic tables in which the patient may lay down or sit upright. When used with an X-ray stereotactic table, the MAMMOTOME biopsy device is attached to a movable, mechanical mounting arm on the table. For one type of table, the patient lies face down on the table and the patient's breast is positioned in an opening. Several X-ray images of the breast are taken from different angles to determine the location of the suspect tissue. Next the mounting arm is manually repositioned so that the MAMMOTOME biopsy device is properly aligned with the breast. Then the mounting arm is manipulated to push the piercing element of the biopsy device into the breast until the tip of the piercing element is positioned alongside the tissue to be sampled. Additional X-ray images are then made to confirm that the port on the distal end of the piercing element is in the proper position to collect the desired tissue samples. The MAMMOTOME biopsy device is then used to retrieve one or more core samples of tissue. Additional X-ray images are taken to confirm the removal of the suspect tissue. Sometimes the MAMMOTOME biopsy device and mounting arm must be repositioned during the procedure so that the tip of the piercing element is in a new location in order to retrieve more tissue samples.
During a procedure for obtaining numerous tissue core samples using a biopsy device such as the MAMMOTOME biopsy device, a substantial amount of fluids must be communicated to and from the tissue-sampling site within the patient's body. Each time the piercing element and/or the cutting cannula are withdrawn from the body to transport the tissue sample for removal from the distal end of the cannula, fluids can escape from the tissue through the biopsy device. In the MAMMOTOME biopsy device, a knockout tube is provided so that as the cutting cannula is withdrawn from the tissue and the distal end of the cutting cannula is outside the body, the distal end of the knockout tube pushes out the core sample automatically from the distal end of the cutting cannula. A drain line is attached to the proximal end of the knockout tube so that fluids contained in the cutting cannula can be removed. This drain line may be attached to a vacuum source to remove the fluids more effectively. Sometimes the operator wishes to disconnect the drain line from the knockout tube in order to inject an additional amount of anesthetic solution (such as lidocaine) into the tissue mass to insure that a sufficient amount is present at the area where the tissue sample will be taken. By removing this drain line, the fluid within the tissue, which may be at a relatively high pressure, can escape from the device. The knockout tube (also referred to as a knockout pin) is disclosed also in U.S. Pat. No. 5,649,547 (Ritchart). The knockout tube and the vacuum chamber are attached to separate vacuum lines fluidly connected to a vacuum source.
Two vacuum lines for removing fluids are also required for another vacuum-assisted, core sampling biopsy device disclosed in PCT international application WO 99/15079 by Farascioni, et al, and published on Apr. 1, 1999. During set-up for this biopsy device, it is also necessary to attach separately each of the two vacuum lines to a vacuum source. After the biopsy procedure is completed, these fluid carrying lines must be drained and removed in order to clean the biopsy device, vacuum source, etc. and set-up a new, sterile set of fluid carrying tubes for the next patient. Any measures, therefore, to facilitate the attachment of these vacuum lines, in both the MAMMOTOME biopsy device and the Farascioni device, will help to shorten the set-up time and prevent spillage of fluids in the surgical environment.
Various disposable, fluid collection devices have been developed in other medical arts for relatively easy set-up and takedown for each patient. For example, a disposable manifold and valve for processing of blood is disclosed in U.S. Pat. No. 4,946,434 issued to Plaisted, et al on Aug. 7, 1990. Similarly, a solution pumping system including a disposable pump cassette is disclosed in U.S. Pat. No. 5,062,774 issued to Kramer, et al, on Nov. 5, 1991. An autotransfusion system and method is disclosed in U.S. Pat. No. 5,885,261 issued to Longo, et al on Mar. 23, 1999. Fluid collection systems are also disclosed for use with surgical devices for phacoemulsification and removal of cataract lens. Examples include U.S. Pat. No. 5,697,898 issued to Devine, et al on Dec. 16, 1997, and U.S. Pat. No. 4,832,685 issued to Haines, et al, on May 23, 1989. All these devices and methods combine the disposable fluid carrying components in a way to allow for easy set-up/takedown, but they are not designed for the type of two-vacuum line fluid collection system required for the aforementioned biopsy devices.
As described in the related patent applications referenced earlier, it is also highly desirable to automate the operation of the core sampling biopsy device to reduce the time of the procedure, insure the correct sequence of steps, and reduce the need for assistance in carrying out the procedure. An automated fluid collection apparatus is especially advantageous in controlling the flow of fluids to and from the biopsy device. It is not necessary, for example, to have a vacuum source continuously supplying vacuum to the biopsy device. Therefore, an "on-off" valve in the vacuum lines connected to the biopsy device may be operated by a control unit programmed for supplying vacuum only during certain steps of the operational sequence. Also, it may be desirable to pulse the vacuum pressure supplied to the vacuum lines in order to free tissue debris which may be lodged in the biopsy device, and this pulsing could be provided by an automated valve actuator responding to an operator command. For biopsy devices having more than one vacuum line such as the MAMMOTOME biopsy device, it is desirable to be able to control automatically the flow of fluids through each line independently. This is important, for example, when it is desired to remove a tissue sample from a patient. Vacuum supplied to the vacuum chamber for pulling the tissue sample into the lateral receiving port must first be "turned off" before the tissue sample can be moved from the distal end of the hollow piercing element to outside the patient's body by retracting the cutting cannula. Vacuum is maintained within a lumen in the cutting cannula to help hold the tissue sample inside the lumen while the cutting cannula is retracted. Therefore, it is important to have independent means for supplying vacuum and ambient pressure to the vacuum chamber and to the lumen inside the cutting cannula.
There are a number of different kinds of valves used in the art for fluid collections systems. One type of valve commonly used is referred to as a "pinch" valve and has an actuator (usually solenoid driven) to pinch shut and release a flexible tubing. A disadvantage of using pinch valves in an automated fluid collection apparatus is the need to use highly flexible, relatively expensive tubing, such as silicone rubber tubing. It is very desirable that the cost of the tubing and other disposable portions of the fluid collection system be minimized to reduce the overall cost of the procedure to the patient. Yet another disadvantage of using pinch valves for an automated biopsy device is the significant time required to position or "thread" the flexible tubing into each pinch valve. This time-consuming step of the fluid collection system set-up usually requires both hands and the full attention of the operator, and there is significant opportunity for error resulting in improper operation of the fluid collection system.
What is needed, therefore, is a fluid collection apparatus for use with an automated biopsy device having at least two vacuum lines, wherein the fluid collection apparatus may be set-up for each patient quickly, easily, and with minimal opportunity for operator error. What is further needed is a fluid collection apparatus in which the disposable portion uses a relatively inexpensive tubing material. What is further needed is a fluid collection apparatus in which each vacuum line is controlled independently and whenever a vacuum source is disconnected from each line, the line is automatically vented to ambient pressure.